It is known that one can record the speed and the distance of a preceding vehicle with the aid of a radar sensor of an adaptive cruise control. These data are used by the adaptive cruise control to regulate in a comfortable manner the speed of the vehicle in dependence upon the traffic situation. In addition, the data of the radar sensor may be used to recognize critical driving situations. Thus, for example, a rear-end collision may be avoided by automatic emergency braking, or its consequences may be greatly reduced.
Moreover, systems are known which, by an unaccustomed vehicle reaction, are intended to point out to the driver a danger situation. Such a vehicle reaction may be implemented either by brief automatic braking, as described in German Patent No. DE 198 57 992, or by a jolt in the power train system, as described in German Patent Application No. DE 38 22 193. Such kinesthetic vehicle reactions that are not influenceable by the driver, experience an unequally higher prioritization by the driver when compared to optical or acoustical warning signals, as compared to the feedback of braking using an antilock system at the brake pedal in contrast to an indication on an instrument cluster.